Shall I file under EB2 or EB3 for GC?

I have a bachelors degree in the STEM field in the US and have worked 5 years after my bachelors completing my 5th year this past December. I am currently on H1B. My employer has decided to start GC processing for me. I fall under ROW (Rest of World) category when it comes to the priority date. The current cut off date for EB3 is 1st Oct 2016 and for EB2 it is current. As my employer is telling me that the PERM preparation takes at least 3-4 months and then once filed it takes 4-6 months for its certification. So, does it make any difference for me to file under EB2 or EB3 as a time wise? By the time my PERM is certified my priority date would be current for EB3 right? and I would face less scrutiny in the EB3 category? or shall I go with EB2 category because I am eligible?